Stabilizer



Feb. 9, 1943. M. B. BRIGGS STABILIZER I 2 Sheets-Sheet l Filed Oct. 30,1937 I the effect of such sudden force.

Patented Feb. 9, 1943 UNITED STATES PATENT OFFICE" STABILIZER MertonB.-Briggs, Pittsburgh, Pa., assignor to I. A. Simon, Pittsburgh, Pa.

Application October 30, 1937, Serial No. 112,034

' 26 Claims.

This invention relates to a stabilizing device and is an improvement onthe structure shown in the United States Patent to MacLellan No.2,058,384, October 20, 1936, and my pending application Serial No.143,157, now Patent No. 2,151,851 issued March 28, 1939, and is used inconnection with the steering mechanism of an automobile.

Stabilizers of this type are designed to be positioned between thechassis of the vehicle and a. movable member of the steering mechanismor are adapted to be connected between relative y movable parts of thesteering mechanism. The stabilizer of this invention includes a closedcylinder adapted to contain fluid in which a piston is reciprocatedunder the influence of the normal operation of the steering mechanism.The fluid will normally flow through a restricted passage in the pistonhead but when any road shock is encountered such as would tend to wrestcontrol of the steering mechanism from the driver, the device becomesinstantly operative to overcome The stabilizer normally presents noappreciable resistance to the usual driving effort, but under anycondition of road shock, the resistance offered to the hydraulic mediume. g. 'oil through the piston head is so great that it momentarilyoperates'the valve means located therein to prevent the flow of fluid,and thus instantaneously prevents movement of the steering mechanismunder the influence of the shock.

It is necessary that the stabilizer be thoroughly reliable at all timesand the present invention ielates to an improved piston that promotesreliability by making the operation of the stabilizer uniform under allconditions of temperature. As will be appreciated, the viscosity of thehydraulic fluid changes under the influence of the temperature and it isan important feature of this invention to provide thermal compensatingmeans to render the operation uniform under all such changes ofviscosity. This thermally re-.

sponsive compensating means is incorporated in 'the piston head and isoperative to effectively maintain the resistance of the flow passageconstant regardless of the viscosity of the fluid.

In stabilizers of this type it has been foun that the instantaneousclosing of the valve'is more effective when the piston is moving in onedirection than when it is moving in the other, that is, the same valvemeans in the piston is more sensitive when moving in one direction thanwhen moving in the other. Therefore, in order to make the operation ofthe device uniform in both directions of piston movement, it is afurther object of this invention to provide means to render theoperation of the valve equally sensitive regardless of the direction ofpiston movement.

'Another object of the invention is to provide a piston head thatembodies the features set out above and is extremely simple inconstruction, easily assembled, and completely reliable in operation.

Referring to the drawings:

Figure 1 is a plan view showing the stablizer associated with aconventional rigid axle front wheel suspension steering mechanism.

Figure 2 is a sectional view of the stabilizer taken on line 2-2 ofFigure 1.

Figure 3 is a sectional view taken on line 3-3 of Figure .2. I

Figure 4 is a sectional view taken on line 4-4 of Figure 2. i

Figure 5 is a sectional view of the piston head showing the bimetallicelement contracted under the influence of a reduced temperature.

Figure 6 is a'sectional view of a preferred form of stabilizer taken online 22 of Figure 1, the same being an improvement on the structureshown in Figure 2.

Figure 7 is a sectional view of the construction shown in Figure 6 andtaken on line 1-4 of Figure 6.

Figure 8 is a sectional view of the construction shown in Figure 6 andtaken on'line 8-8 of Figure 6.

The stabilizer of the MacLellan type as explained in the aforesaidpatent is particularly adapted to be used in connection with thesteering mechanism of an automobile. The method in which such devicesare associated with the steering mechanism is set forth in the saidpatent and my aforesaid application.

Referring to Figure 1, the stabilizer is shown associated with aconventional rigid axle front wheel suspension wherein I0 is the frontaxle and it the tie rod of the vehicle. The stabilizer 12 is connectedbetween the axle and tie rod preferably having its cylinder endconnected to the spring pad 53 by means of the ball joint it and withthe piston end connected to the tie rod by means of a second ball joint[5.

Referring to Figure 2, the stabilizer includes a cylinder I6 closed atits ends by'threaded caps H and adapted to contain a suitable hydraulicsion53 of substantially frusto-conical shape. A

second plate 58 cooperates with the plate'l'ii to confine a compressiblepacking material 55.

This latter plate has a frusto-conical portion terminating in acylindrical portion as shown. The plate 54 is movable, but is heldagainst bodily movement outwardly of the cylinder by the cap I! engaginga spacer member 56 which acts as a stop for the plate as shown. The coilspring 5'! engages a plate 58 in the cylindrical end of the plate 54which plate 58 bears on the packing. The other end of the spring engagesa packing 59 disposed in a recess in the cap l1. By this construction,when the valve locks and I moves in the direction of the packing, thesame is compressed between the movable plate 5| and the plate 54 andthereby caused to flow laterally, and seal the chamber wall andperiphery of the piston rod against leakage of the operating fluid. Astop flange 2D is provided adjacent the inner end of the piston rod I8,-and the portion 2| of the rod between this flange and the extreme innerend of the rod is reduced in diameter and threaded. A piston head 22 isthreadedly fitted upon the end 2| of the piston rod, and between thishead and the stop flange or shoulder 20, there is disposed upon thepiston rod a spacer or ring member 23 having a squared periphery. Asimilar spacer or ring member 26 is positioned between the head and thelock nut 25.

The piston head 22 which closely fits the wall of the cylinder I6 isprovided with a plurality of openings 24 adjacent its periphery, theseopenings being circumferentially spaced as shown in Figure 3. 0nopposite sides of the head and slidably mounted on the spacers 23 and 2Bare bi-metallic discs 21 and 28 of less thickness than the thickness ofthe spacers and which discs are provided with radially extending,circumferentially spaced, arms 29 and 30 respectively that cooperatewith the openings 24 to govern the flow of fluid through the piston head22. It will be observed that the discs are movable upon the spacermembers which act as guides therefor and the spacer members are held infixed relation to the head and the openings 24 therein by means of pins23', 26' respectively so that the arms 29 and 30 are at all timesmaintained in proper registration with the openings 24 in the pistonhead.

The arms 29 and 30 are thermally responsive and form a part of thecompensating means built into the device. The operation of these armswill appear more fully below. A plurality of springs 32 which passthrough openings 24 engage the ends of the arms to resiliently maintainthe discs 21 and 28 and the arms carried thereby spaced away from theadjacent face of the head to normally maintain the flow passage throughthe openings 24 relatively unobstructed. The free area A between thearms 29 of disc 21 is less than the free area B between the arms of disc28, this being for a purpose which will be hereinafter explained. Thesprings 32 are preferably but not necessarily formed of bimetallicmetal.

The operation of the device is as follows:

The stabilizer being positioned between the axle ID and the tie rod IIas shown in Figure 1, during the normal functioning of the steeringmechanism, when the vehicle is turned the tie rod is thereby caused tomove relative to the axle, and the piston 22, moving with the tie rod,will reciprocate in the cylinder l6 and the fluid contained in thecylinder will flow freely back and forth through the openings 24 in thepiston head, i. e. the fluid flows around the edges of the arms 29 or 30as the case may be, through openings 24 in piston head 22 and out aroundthe edges of the arms of the disc on the opposite side of the head.

If any unusual force is encountered by one of the front wheels such as ahole, rut, flat tire, sand, etc., the relative movement between the tierod and axle is greatly and suddenly increased or accelerated due to thesharp diverting force produced by such conditions, which diverting forcewould normally wrest the steering mechanism out of the driver's control.However, when the stabilizer is connected between these parts as inFigure 1, due to the sudden increase in relative movement between thetie rod and axle, the piston is caused to reciprocate at a sharplyaccelerated rate in the cylinder and the velocity of the fluid flowingthrough the piston head is likewise rapidly increased. If for instancethe piston is forced to quickly move to the right in Figure 2 and extraresistance is built up by the oil flowing around the edges of the arms30 which, coupled with the fluid pressure built up against the forwardface of the arms 39 instantaneously overcomes the springs 32 and slidesthe disc 28 and the arms 30 against head 22 whereby the arms cover theopenings 24 and seal the same against passage of fluid. With theapertures 24 sealed, no fluid can flow past the piston head andtherefore, the piston is held against further movement toward the rightrelaj tive to the cylinder. This holding of the piston against movementrelative to the cylinder is momentary but is for a sufficient timeperiod to prevent the steering mechanism from turning in response to theshock and the effect of the shock is arrested. Thus the driver retainscontrol of the vehicle. Stated in another way, with the closing of theopenings or apertures 24, there takes place a momentary locking of theparts which prevents the tie rod II from moving relative to the axle Illso that the shock encountered is not transmitted to the steeringmechanism in a manner to cause the front wheels to divert from theirnormal course and the front wheels are thus momentarily prohibited fromturning.

It is evident of course that if the wheels were suddenly subjected to aforce tending to divert them in the opposite diection causing the pistonto reciprocate to the left in Figure 2 the arms 29 would be seated, andthe operation of the parts would otherwise be exactly as just described.

It will be understood that the discs 21 and 28 and the arms 29 and 30are prevented from seating against piston head 22 during normaloperation because the springs 32 are tensioned to overcome the normalresistance of fluid flow through the piston. But when, as aboveexplained, a sudden shock accelerates the flow of fluid through thepassage and the flow resistance and the fluid pressure on the surface ofthe arms are thereby increased, the tension of springs 32 is overcomeand either the disc 21 and its arms 29 or disc 28 and its arms 3|] areforced against one or the other face of the head depending upon thedirection in which the force of the shock is exerted.

When the shock or diverting force has been dissipated i. e. arrested,the pressure built up in the end of the cylinder will be quicklyreleased by a comparatively slow by-passing of fluid which takes placearound the periphery of head 22 i. e. between the periphery of the head22 and the cylinder wall I 6. This release of pressure takes placesubstantially instantaneously after the shock is arrested, the pressuresonboth sides of the piston head being thus equalized, the springs 32will force the respective seated disc and its arms away from thehead'and normal operation of the steering mechanism is again had. It isto be understood of course that though the head closely fits thecylinder, 9. small amount of fluidwill flow or by-pass around itsperiphery and the releasing action above described is instantaneous oncethe shock or unusualforce has been dissipated.

As previously expressed stabilizers of this type have'been found to bemore sensitive whenthe and thus compensate for an increase in theviscosity of fluid due to a reduced temperature.

It is to be understood that the relative thickness of the bimetallicdiscs 21 and 28 is controlled with relation to the thickness of the ringmembers 28 and 28 or vice versa so that the discs will have a propersliding operation under the forces exerted upon either side of thepiston head, such that the sharp arresting of diverting forces as aboveexplained and instantaneous release of the locking action will beobtained. The thicmessratio will be determined in most cases by thenature of the hydraulic fluid and the internal diameter of the cylinder.

The preferred form of the device is shown in Figures 6 to 8 inclusivewherein a portion to of proportioning the free. or open areas A and Bbetween the arms as and 30 respectivelyand around their ends. It will beappreciated that the velocity of a liquid flowing through a passagedepends upon the cross sectional area of the passage. As the areadecreases the velocity increases, and as the velocity increases theresistance increases. This is known as Bemouli's theorum. The flowpassage in one instance will be from the left hand chamber through thefree area A through the openings 24 through free areas B into the righthand chamber, upon the wheels being turned in the opposite direction theflow will be reversed. Thus referring to Figure 3, the free area Abetween arms 29 is less than the free area 13 between the arms 30 shownin Figure 4, and therefore, a greater resistance is offered by disc 21to the normal flow of fluid. This is preferably accomplished by makingthe overall diameter of the arms 30 less than the overall diameter ofthe arms 29 as shown.

when the piston moves toward the end through which the piston rod entersthe cylinder in the present day stabilizers, the valve. mechanism hasbeen found not to be as sensitive as when moving toward the opposite endof the cylinder. In order to overcome this tendency the resistanceoffered to the flow of fluid from the pistonrod side has, as explained,been made greater by decreasing the free area A between arms 29. So inmoving in thatdirection or toward the left in Figure 2, the usual flowresistance and the increased resistance built up under a shock will asquickly attain sufllcient force to seat the arms against the head aswhen the piston is acted upon by a force causing .it to move in theother direction.

Also it has been found desirable in order to promote a more reliableoperation of the stabilizer to provide means to maintain the flowresistance constant when the viscosity of the fluid changes. This isaccomplished by making the discs 21 and 28 and the arms 29 and 30integral thereon of bimetallic metal. when the temperature varies thebimetallic elements will respond thereto and cause the arms to bend awayfrom or toward the piston head to increase or decrease the distancebetween the arms and the adjacent face of the head and therefore theflow resistance accordingly depending upon whether the viscosity isgreater or less. As shown in Figure 5, the arms have been caused to bendaway from the head to reduce the flow resistance the inner end of thepiston rod is is cut square and the extreme end is threaded as at M. Thediscs 39 and d8 of bimetallic metal and the piston head as are providedwith square apertures in their central .portions to slidably flt ontothe squared portion 39 of the piston rod. The said discs as and dd areprovided with integral bi-.

metallic arms M and d2 respectively which have depressions 6% formedadjacent their outer extremities that cooperate with apertures oropenings at in piston head t3, the apertures 65 being similar toopenings 2 3. The discs and piston head are mounted in spaced relationon the end 38 of the piston rod and are held in fixed relation by nut41. A spacing ring at is placed; between disc at and nut d1 so that thenut wiil'not interfere with the flexing of the arm 32 either due tofluid movement or to temperature changes. Thearms 4i and 42 are heldspaced from the piston head preferably by bi-metallic springs 49positioned in the openings or apertures 85 and retained between theextremities of the arms 4| and 42, the depressed portions as of which ofthe spring increases as the temperature induced temperatures.

creases. The reverse is true when the inner metal of the helical formhas the greater coeflicient of expansion. This characteristic of abi-metallic spring has been taken advantage of to obtain the increasedtension desired when the working fluid increases in viscosity due to re-By winding the spring so that the inner metal has the greater coemcientof expansion, the tension of the spring increases as the temperaturedecreases.

Referring to Figure 6, the packing I9 includes a gland housing 60 whichis held in position against the cap I! and the adjacent end of thecylinder as shown. The housing at its inner end is provided with acircular flange 6| defining an opening of substantially greater diameterthan the diameter of the piston rod whereby fluid may act upon thepacking within the housing. Within the housing there isdisposed amovable plate 62 exposed to the fluid as shown and bearing against saidflange SI for confining layers of compressible packing material 63. A

coil spring 64 bears "against a movable plate 65 which confines thepacking within the housing at that end thereof. The spring at itsopposite end engages a packing 66 disposed in the recess These springsFigure 6 is the same as explained with reference to the device shown inFigure 2 except that the arms 4| and 42 flex about the spacers 48'instead of having the discs carrying the arms slide into engagement withthe head. This is possible because the depressions 48 flt into and sealthe apertures 45. The depressions 46 and the bimetallic springs 49 makefor a more sure and even operation of the stabilizer under allconditions. It is seen that the springs increase or decrease theirtension to balance out changes in flow resistance caused by viscositychange of the fluid and the depressions 4B insure the complete coverageand sealing of apertures 45 as-the bimetallic arms 4| and 42 are causedto warp under changes of temperature,

Bleeder openings can, of course, be formed in the ends of the arms 21and 28 in registered relation with the opening 24 or in the depressions46 to register with the openings 45, but it is preferred to by-pass thefluid between the periphery of the piston head and the wall of thecylinder.

It is to be understood that the invention herein shown and described issubject to numerous other modifications and variations, all of which areconsidered to be comprehended within the scope of the appended claims.

I claim:

1. A stabilizer of the type described having a cylinder adapted tocontain a fluid and a piston adapted to reciprocate therein, said pistonmeans comprising a head provided with openings, said head being mountedadjacent the end of the piston rod and having disks mounted on oppositesides thereof, said disks being provided with a plurality of arms thatcooperate with said openings to control the flow of fluid through saidhead, said arms being adapted to permit free flow under normal flowcondition and to cut off flow under the conditions existing when anabnormal shock is encountered, and said arms being thermally responsiveto compensate for viscosity changes of the contained fluid. t

2. A stabilizer of the type described having a cylinder adapted tocontain a fluid and a piston adapted to reciprocate therein, said pistoncomprising a head having a plurality of openings therethrough, said headbeing mounted adjacent the end of the piston rod and having disksmounted on opposite sides thereof, said disks being provided withbimetallic arms to cooperate with said openings and being adapted tocompletely close said openings when an abnormal shock is encountered tocontrol the flow of fluid through the piston.

3. A stabilizer of the type described having a cylinder adapted tocontain a fluid and a piston adapted to reciprocate therein, said pistoncomprising a head having openings therein, said head being mountedadjacent the end of the piston rod and being provided with disks onopposite sides thereof, said disks having arms to cooperate with saidopenings, the free area between said arms and around their ends being soproportioned as to control the normal flow resistance of the pistonhead.

4. A stabilizer including a cylinder adapted to contain a fluid and apiston adapted to reciprocate therein, said piston having an aperturedhead and thermally responsive compensating means cooperating with saidapertures positioned on opposite sides of said head, said means beingoperative to normally permit a free flow of fluid through said head andbeing operative to cut off the flow of fluid when an abnormal shock isencountered, said means being also operative to compensate for changesin the viscosity of the hydraulicfluid contained in said cylinder.

5. A stabilizer including a cylinder adapted to contain a fluid and apiston, adapted to reciprocate therein, said piston having an aperturedhead with disks mounted on opposite sides thereof, said disks havingarms cooperating with said apertures and being adapted to completely cutoil flow of fluid through said piston when an abnormal shock isencountered, said disks and arms forming compensating means to make theaction of the device uniform in both directions of movement under allconditions.

6. A stabilizer including a cylinder adapted to contain a fluid and apiston adapted to reciprocate therein, said piston having an aperturedpiston head and disks mounted on opposite sides thereof, said disksbeing provided with arms adapted to cooperate with said apertures, saidarms being bimetallic and normally held spaced from said apertures andbeing adapted to substantially close said apertures only when anabnormal shock is encountered.

7. A stabilizer including a cylinder adapted to contain a fluid and apiston adapted to reciprocate therein, said piston having an aperturedhead having disks mounted on opposite sides 'thereof, said disks beingprovided with arms adapted to cooperate with said apertures, said armsbeing normally held spaced from said apertures by bimetallic springs.

8. A stabilizer of the type described comprising a cylinder adapted tocontain a fluid and a piston adapted to reciprocate therein, said pistonbeing provided with an apertured head having disks mounted on oppositesides thereof, said disk being provided with bimetallic arms tocooperate wtih said apertures, said arms being normally resilientlyspaced away from said apertures by bimetallic springs passing throughsaid apertures.

9. A stabilizer of the type described comprising a cylinder adapted tocontain a fluid and a piston adapted to reciprocate therein, said pistonhaving an apertured head having disks disposed on opposite sidesthereof, said disks being proso that fluid may pass freely therethroughduring reciprocation of the piston, said arms being adapted to movefromsaid spaced position to substantially instantaneously seal saidopenings against the flow of any fluid therethrough when an abnormalspeed of reciprocation is imparted to said means whereby furtherreciprocation of said means is instantaneously and completely arrestedunti1 the force tending to produce such abnormal speed is overcome.

- '11. A stabilizer of the type described having a cylinder adapted tocontain a hydraulic fluid, a piston means adapted to reciprocatetherein,

said means including a head having a plurality of openings therein, saidhead being mounted adjacent the end of the piston rod, discs positionedon opposite sides of said head, said discs being slidably mounted onsaid piston rod and being provided with arms cooperating with saidopenings, said arms being resiliently spaced from said openings by aplurality of springs so that fiuid'may pass freely therethrough duringreciprocation of the piston and being adapted to move from said spacedposition to substantially instantaneously seal said openings against theflow of any fluid therethrough when an abnormal speed of reciprocationis imparted to said means whereby further reciprocation of said means isinstantaneously and completely arrested until the force tending toproduce such abnormal speed is overcome.

12. A stabilizer of the type described having a cylinder adapted tocontain a hydraulic fluid, a piston means adapted to reciprocatetherein, said means including a head having a plurality of openingstherein, said head being mounted adjacent the end of the piston rod,discs positioned on opposite sides of said head, said discs beingslidably mounted onsaid piston rod and being provided with armscooperating with said openings, said arms being resiliently spaced fromsaid openings by a plurality of springs positioned in said openings andengaging the ends of said arms so that fluid may pass freelytherethrough during reciprocation of thepiston and said arms beingadapted to move from said spaced position to substantiallyinstantaneously seal said openings against the fiow of any fluidtherethrough when an abnormal speed ofreciprocation is imparted to saidmeans whereby further reciprocation of said means is instantaneously andcompletely arrested until the force tending to produce such abnormalspeed is overcome.

13. A stabilizer of the type described having a cylinder adapted tocontain a hydraulic fluid, a piston means adapted to reciprocatetherein, said means including a head having a plurality of openingstherein, said head being mounted ad.- iacent the end of the tioned onopposite sides of said head, said discs being fixedly mounted on saidpiston rod, said discs being provided with arms cooperating with saidopenings, said armsnormally eing resiliently spaced from said openingsby a plurality of springs positioned in said openingsand engaging saidarms so that fluid may pass freely therethroughduring reciprocation ofthe piston and said arms being adapted to flex from said spaced positionto substantially seal said openings against the flow or any fluidtherethrough when an abnormal speed of reciprocation is imparted tosaidmeans whereby further reciprocation of said-means. is instantaneouslyand completely arrested until the force tending to produce such abnormalspeed is overcome.

14. In a stabilizing device, a cylinder containing liquid, a rod havinga piston slidably mounted in the cylinder, and yieldinglyconnectedpressure responsive valve means, one associated with-eachsideof the piston to permit the rod to move freely in either direction inthe cylinder below a predetermined speed and to check the movement ofthe rod within the cylinder above said predetermined speed, the valvemeans remote from the rod being smaller in area than the valve meansadjacent the rod 15. A steering stabilizer for a vehicle comprising acylinder and rod one of which is attached means on each piston rod,discs, posito a fixed part of the vehicle and the other to a movablepart of the steering mechanism, liquid L in the cylinder, a pistoncarried by the rod and slidable in the cylinder and having an opening, apair of valve means associated with said piston, each of which isoperable at times to close said opening, resilient means common to bothvalve means and disposed in said opening and one of said valve meanshaving a smaller area than the other.

16. In a device to check movement in excess of a predetermined speed, acylinder having a quantity of liquid therein, a rod movable in thecylinder, a piston having an aperture and carried by the rod, a pressureresponsive valve side of the piston for control of the aperture throughthe piston, a common spring means passing through the aperture andpositioned between the valve means normally retaining the valve meansopen, said valve means operable to check the flow of liquid in eitherdirection through the piston when a predetermined pressure is developed.

17. A stabilizer for the steering mechanism of a vehicle comprising aliquid containing cylinder and a piston movable therein, said stabilizeradapted for connection between a part of the vehicle stationary withrespect to the steering mechanism and the steering mechanism, saidpiston having an intermediate portion slidably engaging the inside faceof the cylinder, the end parts of the piston, one on each side of saidintermediate portion, being of substantially less diameter than theinside of the cylinder, a valve member slidably mounted on each of saidparts and springs normally holding each member away from saidintermediate portion, said intermediate portion having at least onepassage extending through it at a location radially outward from the endparts, said piston being impassable to the fiow of liquid radiallyinward from said passage, and a passageway at each member extending fromone side of the member to the other, the passageways at the membersbeing out of alignment with the passage in the intermediate portion,when said members are in normal position a substantial flow beingpermitted through a passageway at one of said members, thence radiallybetween said latter memberand said intermediate portion, thence throughsaid passage, thence radially between the other member and theintermediate portion and then through the passageway at said othermember, the first of said members substantially closingv oil the spacebetween itself and the intermediate portion when a sudden relativemotion of the piston and the cylinder displaces said first member fromits normal position.

18. A stabilizer for the steering mechanism of a vehicle comprising aliquid containing chamber and a plunger movable therein, said stabilizeradapted for connection between a part of the vehicle stationary withrespect to the steering mechanism and the steering mechanism, saidplunger having an intermediate portion with its engaging the inside faceof the chamber substantially preventing liquid from passing between saidperiphery and said face, the end parts of the plunger being of lesscrosssection than said intermediate portion, a valve member slidablymounted on each of said parts,

and springs normally holding the members away from said intermediateportion, said intermediate portion having at least one passage extendingthrough it at a location radially outward from the end parts, saidplunger being impassable to flow of liquih radially inward from saidpassage, said members having their outer periphery noncircular inoutline providing thereby passages between the members and to the insideof the chamber for permitting a substantial flow of liquid from one sideof them to the other, said members having imperforate portions oppositethe ends of said passage, the members when in normal position permittingliquid to flow through said passage, said latter'flow beingsubstantially cut off when a sudden relative motion of the plunger andchamber displaces a member from its normal position to move it to theintermediate portion.

19. A stabilizer for the steering mechanism of a vehicle, comprising aliquid containing chamber and a plunger movable therein, said stabilizeradapted for connection between a part of the vehicle stationary withrespect to the steering mechanism and the steering mechanism, saidplunger having a portion with its periphery slidably engaging the insideface of the chamber substantially preventing liquid from passing betweensaid periphery and said face, valve members adjacent said portion one oneach side thereof and slidable to and from said portion, said portionhaving-a plurality of passages extending through it, and springsextending through said passages into contact with the members on eitherside of said portion for normally holding the members away from saidportion, said members having imperforate portions opposite the ends ofsaid passages, said members when in normal position permitting liquid toflow through said passages, said latter flow being substantially cut oilwhen a sudden relative motion of the plunger and chamber displaces amember from its normal position to move it to said portion.

20. A steering stabilizer mechanism comprising a cylinder, a rodslidably mounted therein, an apertured piston attached to one end of therod, disc valves mounted on both faces of the piston, and yielding meansurging said discs away from the piston, the disc valve remote from therod being smaller than that adjacent the rod.

21. An apertured piston attachable to a rod, and valve means mountedthereon regulating fiow through the apertures, comprising discs on bothsides of the piston axially slidable in relation to the piston, andmeans yieldingly urging the discs apart, the disc remote from the rodattachment being of smaller diameter than the disc adjacent the rodattachment.

22. In a steering stabilizer for vehicles, a cylinder having a quanttiyof liquid therein, a rod slidably mounted in the cylinder, connectingmeans between the cylinder and rod and a fixed part of the vehicle and amovable part of the steering mechanism, an apertured piston carried bythe rod, pressure responsive valve means comprising spaced discspositioned adjacent said piston, and yielding means urging the discsaway from the piston to enable liquid to flow through the aperturedpiston when the velocity of travel of the rod is below a predeterminedvalue, the disc remote from the rod having an area smaller than the discadjacent the rod.

23. In a steering stabilizer for vehicles, a cylinder having a quantityof liquid therein, a rod slidable within the cylinder, valve meanscarried by the rod comprising an apertured body member, spaced discsadjacent the body member and adapted to close the apertures in the bodymember under certain operating conditions, one of said discs having asmaller area than the other, and yielding means common to both discs andpassing through the apertured body member for urging the spaced discsaway from the body member.

ing liquid, a rod having a piston slidably mounted in the cylinder, andyieldingly connected pressure responsive valve means, one associatedwith each side of the piston to permit the rod to move freely in eitherdirection in the cylinder below a predetermined speed and to check themove ment of the rod within the cylinder above said predetermined speed,the valve means remote from the rod being smaller in area than the valvemeans adjacent the rod to allow speedier passage of liquid as comparedto passage in the opposite direction, shoulders positioned on oppositesides of and fixed with respect to said piston, spacing means confinedbetween said piston and said shoulders, said valve means being slidablymounted on said spacing means between said shoulders and said pistonwhereby when said valve means are moved against said piston in responseto a speed above said predetermined speed the rod movement is stopped.

25. In a stabilizing device, a cylinder containing liquid, a rod havinga piston slidably mounted in the cylinder, and yieldingly connected pressure responsive valve means, one associated with each side of the pistonto permit the rod to move freely in either direction in the cylinderbelow a predetermined speed and to check the movement of the rod withinthe cylinder above said predetermined speed, the valve means remote fromthe rod being smaller in area than the valve means adjacent the rod toallow speedier passage of liquid as compared to passage in the oppositedirection, shoulders spaced from opposite sides of said piston, andspacing means between said piston and shoulders, said valve means beingslidably mounted on said spacing means and being normally biased byreason of said yielding connection toward said shoulders, said valvemeans being slid against said piston to cut off the flow of liquidthrough the piston when said rod moves above said predetermined speedwhereby further movement of said rod is checked.

26. In a device to check movement in excess of a predetermined speed, acylinder having a quantity of liquid therein, a rod movable in thecylinder, an apertured piston carried by the rod, pressure responsivevalve means associated with each side of the piston, and a compressiblemember normally retaining the valve means open. said valve meansoperative to check the flow of liquid in either direction through thepiston when a predetermined pressure is developed, the valve means onthe side of the piston adjacent to the rod being designed to respond toa lesser pressure than the valve means remote from the rod, to allowslower passage of liquid as compared to passage in the oppositedirection.

MERTON B. BRIGGS.

24. In a stabilizing device, a cylinder contain-

